323 
HOLOPTYCHIIDiE. 
wrinkles, occasionally replaced by tubercles. Head depressed, the 
bones superficially granulated ; teeth compressed, with a pair of 
sharp edges at least in the upper portion; anterior median jugular 
plate absent. Pelvic fins obtusely lobate, situated at or behind 
the middle of the body ; first dorsal fin opposite the pelvic pair, 
second dorsal opposite or partly posterior to the anal; tail hetero- 
cercal, the upper lobe of the caudal fin small, the lower lobe 
triangular and obliquely truncated. 
I. Holoptychitjs proper. 
Holoptychius nobilissimus, Agassiz. 
1835. Gyrolepis giganteus, L. Agassiz, Poiss. Foss. vol. ii. pt. i. p. 175, 
pi. xix. fig/13. 
1839. Holoptychus nobilissimus, L. Agassiz, in Murchison’s Silur. Syst. 
p. 600, pi. ii. bis. figs. 1, 2 (specific name giganteus withdrawn). 
1841. Holoptychius nobilissimus, H. Miller, Old Red Sandst. p. 162, 
pi. ix. fig. 2. 
1844. Holoptychius murchisoni, L. Agassiz, Poiss. Foss. V. G. R. p. 72, 
pi. xxii. fig. 2. [Scales.]— <pe<S7- c (X/, 
1845. Holoptychius nobilissimus, L. Agassiz, ibid. pp. 73, 140, pi. xxiii., 
pi. xxiv. fig. 2, (P) pi. xxxi. a. fig. 26. 
1855. Holoptychius nobilissimus (‘ P amend to noblei ’), F. M‘Coy, Brit. 
Palseoz. Foss. p. 595. 
1860. Holoptychius nobilissimus , E. von Eicliwald, Leth. Rossica, vol. i. 
p. 1572. 
1888. Holoptychius nobilissimus, M. Lohest, Ann. Soc. Geol. Belg. 
vol. xv. pp. 127, 139. 
1888. Holoptychius deivalquei , M. Lohest, ibid. p. 134, pi. i. fig. 5, 
pi. ii. figs. 1-4, pi. iii. figs. 1, 3, 5, 6, pi. v. figs. 1-3. [Scales; 
M. Lohest Collection, Liege.] 
1890. Holoptychius nobilissimus, Woodward & Sherborn, Cat. Brit. 
Foss. Vertebrata, p. 97. 
1890. Holoptychius nobilissimus, R. H. Traquair, Proc. Roy. Soc. 
Edinb. vol. xvii. p. 388. 
Type. Fish wanting caudal extremity, ventral aspect; British 
Museum. 
The type species, of very large size. Head and opercular 
apparatus occupying about one-fifth of the total length. Scales 
externally ornamented with numerous large branching ridges, often 
interrupted and partly tubercular on the ventral aspect of the 
abdomen, continuous and more delicate on the caudal pedicle; the 
superficial ridges rarely alternating with, and continued by, scries of 
small tuberculations at the anterior edge of the exposed area of the 
scale. 
